plotPNG function

Capture a plot as a PNG file.

The PNG graphics device used is determined in the following order:

• If the ragg package is installed (and the shiny.useragg is not set to FALSE), then use ragg::agg_png().
• If a quartz device is available (i.e., capabilities("aqua") is TRUE), then use png(type = "quartz").
• If the Cairo package is installed (and the shiny.usecairo option is not set to FALSE), then use Cairo::CairoPNG().
• Otherwise, use grDevices::png(). In this case, Linux and Windows may not antialias some point shapes, resulting in poor quality output.

plotPNG(
  func,
  filename = tempfile(fileext = ".png"),
  width = 400,
  height = 400,
  res = 72,
  ...
)

Arguments

• func: A function that generates a plot.
• filename: The name of the output file. Defaults to a temp file with extension .png.
• width: Width in pixels.
• height: Height in pixels.
• res: Resolution in pixels per inch. This value is passed to the graphics device. Note that this affects the resolution of PNG rendering in R; it won't change the actual ppi of the browser.
• ...: Arguments to be passed through to the graphics device. These can be used to set the width, height, background color, etc.

Returns

A path to the newly generated PNG file.

Details

A NULL value provided to width or height is ignored (i.e., the default width or height of the graphics device is used).